Antenatal CTG in midwife-led care Monitoring the journey Elise Neppelenbroek
Antenatal CTG in midwife-led care Monitoring the journey Elise Neppelenbroek
Antenatal CTG in midwife-led care Monitoring the journey Provided by thesis specialist Ridderprint, ridderprint.nl Printing: Ridderprint Layout and design: Jolanda Hiddink, persoonlijkproefschrift.nl This thesis was financed and prepared within the department of Midwifery Science, Amsterdam UMC, location VUmc, Midwifery Academy Amsterdam Groningen, Amsterdam Public Health, Quality of Care, University of Groningen, University Medical Center Groningen, Department of General Practice & Elderly Care Medicine. ISBN nummer: 978-94-6506-944-9 2025 © Elise Neppelenbroek All rights reserved. No parts of this thesis may be reproduced, stored in a retrieval system or transmitted in any form or by any means without permission of the author.
VRIJE UNIVERSITEIT ANTENATAL CTGIN MIDWIFE-LED CARE Monitoring the journey ACADEMISCH PROEFSCHRIFT ter verkrijging van de graad Doctor of Philosophy aan de Vrije Universiteit Amsterdam, op gezag van de rector magnificus prof.dr. J.J.G. Geurts, volgens besluit van de decaan van de Faculteit der Geneeskunde in het openbaar te verdedigen op dinsdag 6 mei 2025 om 15.45 uur in de universiteit door Elise Marjanne Neppelenbroek geboren te Dalfsen
promotoren: prof.dr. C.J.M. Verhoeven prof.dr. A. de Jonge copromotor: dr. O. van der Heijden promotiecommissie: prof.dr. M.W. van Tulder prof.dr. M. Nieuwenhuijze prof.dr.S. Repping dr. P.C.A.M. Bakker dr. M.A.A. Klapwijk-Hermus
TABLE OF CONTENTS Chapter 1 Introduction 9 Chapter 2 Inter- and intraobserver agreement of antenatal cardiotocography assessments by maternity care professionals: A prospective study 21 Chapter 3 Antenatal cardiotocography in Dutch primary midwife-led care: Maternal and perinatal outcomes and serious adverse events. A prospective observational cohort study 45 Chapter 4 Antenatal cardiotocography in primary midwife-led care: Women’s satisfaction 81 Chapter 5 Antenatal cardiotocography in primary midwife-led care: a budget impact analysis 103 Chapter 6 Understanding how Midwife-Led Continuity of Care can be implemented and under what circumstances: a realist review 127 Chapter 7 General discussion 189 Chapter 8 Summary 205 Appendices Samenvatting 214 Supplementary files 219 List of publications 220 PhD Portfolio 221 About the author 222 Dankwoord 223
ABBREVIATIONS aCTG antenatal cardiotocography C contexts CMOC context-mechanism-outcome configurations CQI consumer quality index FIGO International Federation for Gynecology and Obstetrics MRc mechanism resources MRp mechanism responses MLC midwife-led care MLCC midwife-led continuity of care NHS national health system OLC obstetrician-led care O outcomes RCT randomized controlled trial VBHC value-based healthcare WHO world health organisation
‘Niets is moeilijker om aan te pakken, niets gevaarlijker om uit te voeren en niets meer onzeker wat betreft de uitkomsten dan het initiatief te nemen om verandering te introduceren’ Machiavelli, 1532
CHAPTER 1 Introduction
10 Chapter 1 In many countries, the healthcare sector is facing major challenges such as increased demand for healthcare services, capacity problems in hospitals, and rising healthcare costs.1 Without significant changes to the current system, the three essential elements of a good healthcare system – accessibility, affordability, and high quality – will inevitably come under pressure.2 To keep healthcare sustainable, changes are needed. As a result, healthcare professionals have adopted the principles of Value-Based Healthcare (VBHC) which have gained momentum nationally and internationally.3 VBHC is a system that prioritizes individual health goals in relation to choices and decisions of care and quality improvement while making optimal use of resources (money, time, carbon, and space).4 A basic feature of VBHC is to provide care in a setting with the highest value: low-complexity care is not provided in expensive settings (i.e., hospitals or specific hospital departments) by expensive care providers (medical specialists and specialized nurses) but rather in lower-cost settings outside the hospital. To achieve this, substitution of care may be required. In the Netherlands, government policy has focused on shifting care from hospital to out-of-hospital care settings.5 As an example, in Dutch maternity care, antenatal cardiotocography (aCTG) was introduced as a pilot experiment in midwife-led primary care (MLC) for specific indications. Until recently, aCTG was only performed in obstetrician-led care (OLC) in a hospital setting. Recent technological developments in healthcare facilitated the performance of MLC-aCTG in primary care by trained midwives using a portable CTG system to be used at the pregnant woman’s home or in the midwifery practice.6 Value-Based Healthcare Globally, the most common model for healthcare delivery and payment is a feefor-service model that reimburses healthcare providers for the services provided.7 This model has been criticized for incentivizing the overuse of healthcare services, contributing to skyrocketing healthcare costs, and straining the healthcare system.7,8 In recent decades, new insights have been developed that have led to a growing interest in the concept of value in healthcare.9 Rather than focusing solely on output or reducing costs, healthcare providers are encouraged to focus on creating value for patients. Porter and Teisberg introduced the concept of VBHC.9 They define the value of a healthcare service as the outcome relative to all costs incurred to achieve that outcome, with the aim of aligning incentives to deliver high-quality, cost-effective care that improves patient outcomes, as opposed to the traditional fee-for-service model. Patient value is one of the key elements of VBHC. Results of care that matter to patients include clinical outcomes of disease and recovery as well as patients’ wellbeing and experiences with care.10 To create value for patients, it is necessary to 1)
11 Introduction create insight into patient-important outcomes of care and 2) organize care services, evaluation, and continuous improvement around patients rather than providers. Time-driven activity-based costing has been proposed as the cost component of VBHC capable of addressing costing challenges. The traditional activity-based costing model has been difficult for many organizations to implement. One reason is that it is too resource-intensive in large or complex organizations. Time-driven activity-based costing has demonstrated some success in the production and service industries. The emphasis is on accuracy over precision, i.e., ‘approximately right rather than precisely wrong’.11 Accuracy is defined by how close a cost estimate is to the actual cost, and precision as the number of decimal places include in an estimation. Time-driven activity-based costing requires fewer resources than activity-based costing because it only needs two key parameters: the capacity cost rate and the time required to perform activities in service delivery – hence the name “time-driven” activity-based costing. In 2011, Robert Kaplan and Michael Porter presented a sevenstep approach (Table 1) for applying time-driven activity-based costing in healthcare settings to solve the cost crisis, and linked it to the VBHC agenda.12 Table 1: The seven steps of time-driven activity-based costing for health care organizations. Step 1 Select the medical condition. Step 2 Define the care delivery value chain, i.e., chart all the key activities performed within the entire care cycle. Step 3 Develop process maps that include each activity in patient care delivery and incorporate all direct and indirect capacity-supplying resources. Step 4 Obtain time estimates for each process, i.e., obtain time estimates for activities and resources used. Step 5 Estimate the cost of providing patient care resources, i.e., all direct and indirect resources involved in providing care. Step 6 Estimate the capacity of each resource and calculate the capacity cost rate. Step 7 Calculate the total cost of patient care. Insight into clinical outcomes, patient experiences, and costs can contribute to valuebased care at multiple levels. First, individual outcomes in the clinic are used for screening and monitoring symptoms and better informed shared decision-making. Second, through the evaluation of population outcomes, professionals can learn from the analysis of data and improve care for patients with certain conditions or diseases. Third, by benchmarking group outcomes, unwarranted variation and best practices can be identified. Organization of Maternity Care Variations in culture, history, politics, and healthcare policy have led to different ways of organizing maternity care in different countries.13 In the Netherlands, pregnant women at low risk of complications receive MLC from primary care midwives. In contrast, women at high risk of complications receive OLC from obstetricians, 1
12 Chapter 1 obstetric residents, and hospital-based midwives.14,15 If a significant risk factor or a complication arises during pregnancy or labor in MLC, the midwife refers the woman to OLC for consultation or transfer of care. One of the aims of risk stratification is based on the level of risk is to provide the most appropriate care with the resources available, leading to optimal pregnancy outcomes. However, referral to a different care provider may be associated with potential risks, including loss of information and inconsistencies in advice and information due to discontinuity of care.16,17 Discontinuity of care is associated with reduced client satisfaction, inaccurate communication, and an increase in interventions.16-18 In a Dutch survey, maternity care professionals and other stakeholders indicated that the optimal maternity care system is client-centered, and continuity of care should be given to women during labor and birth.22 Opinions differed regarding the optimal maternity care organization model and type of continuity of care. Although stakeholders agreed that care provided in different echelons should be seamlessly connected, some thought that primary care midwives should continue to look after women with medium risk factors whereas others felt that obstetricians should be responsible in these cases. Midwife-led continuity of care (MLCC) has been found to lead to better maternal and perinatal outcomes, higher satisfaction for women, and increased job satisfaction for midwives.19-21 Implementation of MLCC innovations will affect resources from stakeholders. These resources may be material, financial, social, emotional, or political.23 This, in turn, will trigger a certain reasoning and response from stakeholders, leading to intended or unintended outcomes.23,24 The impact of a complex intervention, such as MLCC, is highly dependent on the context in which it is delivered and how successfully it is implemented.25 It is, therefore, necessary to identify the contexts and mechanisms that will lead to the successful implementation of MLCC in high-income countries. Furthermore, the global healthcare system is under increasing pressure, leading to capacity problems. The main factors contributing to capacity problems in maternity care include a chronic shortage of staff in both MLC and OLC, limited physical space in hospitals, and a rising referral rate.5,26,27 To ensure the provision of high-quality care in the near future, alternative approaches will be needed. Previous studies have shown that reorganizing and shifting tasks and responsibilities between MLC and OLC could reduce the number of women referred to obstetrician-led care.17,28 This will help to balance the workload between MLC and OLC and generate cost savings.5,29 Moreover, expanding the practice of primary care midwives could play an important role in improving the value of care, as shifting responsibilities from secondary care to primary care could improve continuity of care for pregnant women.30
13 Introduction Antenatal CTG Some pregnancies may be complicated by a medical condition in the mother or a condition that may affect the health or development of the baby. Although there is no clear evidence that aCTG improves perinatal outcomes31, guidelines generally recommend the use of aCTG to assess fetal well-being during pregnancy in women at increased risk of complications.32-35 The CTG, a continuous electronic recording of the fetal heart rate, is obtained through an ultrasound transducer placed on the mother’s abdomen. A second transducer is placed on the mother’s abdomen to record any uterine activity. The maternal pulse is monitored using a finger probe. The fetal heart rate, maternal pulse, and uterine activity are monitored simultaneously.31 Antenatal CTG is most commonly performed in the third trimester of pregnancy (after 28 weeks). The underlying theoretical concept for the use of aCTG is that it is a test to identify babies with chronic hypoxia or at risk of developing chronic hypoxia.36 An ideal test has both high specificity and high sensitivity (100%). CTG has a high sensitivity (95%) but a low specificity (20%).36 This means that CTG can correctly identify a fetus not at risk, but in the case of a non-reassuring CTG, a large number of fetuses will show abnormalities on the CTG without being at risk of chronic hypoxia. However, if CTG is performed and interpreted as non-reassuring, this may lead to further action (further testing, hospital admission, induction of labor, or cesarean section).31 The introduction of ultrasound and electronic fetal monitoring in the 1970s contributed to a shift in emphasis from mainly maternal outcomes to both maternal and fetal outcomes.37 Concerns about the role of electronic fetal monitoring in the rising rates of cesarean section in high-income countries were raised about a decade after its introduction.37 One of the main disadvantages of the CTG is that there is substantial variation in the interpretation of CTG patterns. Several classification systems exist to classify CTG patterns, of which the International Federation for Gynecology and Obstetrics (FIGO) guidelines are probably the most widely accepted. Previous research on CTG assessment has shown variation between groups of healthcare professionals in obstetrician-led care.38 Although the interobserver agreement in the assessment of reassuring aCTGs is fair to good, low interobserver agreement was found for non-reassuring aCTGs.39,40 There is also variation in the assessment of the different CTG components: baseline heart frequency, accelerations, and contractions showed good to excellent interobserver agreement in aCTG assessment, whereas other CTG components such as variability and the number of decelerations did not.38,39,41 The baseline, variability, accelerations, and decelerations components all showed higher levels of intraobserver agreement than interobserver agreement.42 1
14 Chapter 1 In the Netherlands, CTG knowledge is currently included in the initial training of both doctors and midwives. However, fetal monitoring with a CTG has not been the task of community midwives so far, and the aCTG procedure is mostly performed as part of OLC. As a result, approximately 21,000 women (12%) per year need to be referred to OLC for aCTG consultation. However, most of these aCTGs are reassuring, and these women are referred back to MLC. Therefore, many referrals could be prevented if community midwives perform aCTG in MLC for specific indications. To our knowledge, there is no research on the performance and interpretation of CTG by primary care midwives. The antenatal CTG study Since 2014, three regions in the Netherlands (Nijmegen, Zwolle, and Amsterdam) started a pilot with an innovative initiative based on VBHC principles. Antenatal CTGs were performed for healthy pregnant women between 28 and 42 weeks in situations that pose an increased risk, including decreased fetal movements, external cephalic version in primary care and postdate pregnancy (from 41+0 weeks). A trained midwife performed the external cephalic version in primary care according to a national standard.43 Pregnant women were offered the option of MLC-aCTG or OLC-aCTG. If they opted for MLC, the aCTG was autonomously performed and assessed by a primary care midwife. Another primary care midwife performed a real-time second assessment. Midwives are authorized to perform aCTG provided they are competent by training and experience.44 In the case of a reassuring MLC-aCTG, an ultrasound scan was performed within 24 hours in primary care to assess fetal growth, amniotic fluid, and presentation of the fetus. Blood pressure was also measured. If aCTG, ultrasound, and blood pressure findings were normal, antenatal care was continued in MLC. If an MLC-aCTG was classified as non-reassuring or of insufficient quality, the woman was immediately referred to OLC for follow-up. The introduction of MLC-aCTG for specific indications is expected to address capacity problems in hospitals and rising healthcare costs. It may also improve satisfaction with care by reducing unnecessary referrals in women with a reassuring aCTG. This change in the care pathway is accompanied by a restructuring of tasks and responsibilities, which requires evaluation of the quality of care. However, to date, no research exists on how this expansion of roles in midwife-led care with aCTG relates to the VBHC parameters: clinical outcomes, experience of care, and healthcare costs.
15 Introduction Outline of the thesis The work presented in this thesis was conducted alongside the implementation pilot. The thesis focuses on the clinical process, experience, and cost outcomes of implementing aCTG in midwife-led care. The aims were: 1. To assess the level of inter- and intra-observer agreement between different groups of maternity care professionals regarding the overall classification and the various components of aCTG. 2. To evaluate the process-, maternal- and perinatal outcomes and serious adverse events of women receiving aCTG in midwife-led care. 3. To determine the satisfaction of pregnant women who received aCTG in midwifeled care. 4. To evaluate the budget impact of implementing aCTG in midwife-led care compared to aCTG in obstetrician-led care for women with specific indications in the Netherlands at a national level. 5. To conduct a realist review of the interactions between contexts, mechanisms, and outcomes in order to understand how and under what circumstances continuity of care by midwives can be implemented. Chapter 2 shows the results of a study on the level of interobserver and intra-observer agreement for aCTG assessments between and within four professional groups involved in Dutch maternity care regarding the overall classification and assessment of the various components of aCTG. Chapter 3 reports the results of a prospective cohort study conducted among women who received an MLC-aCTG, focusing on the care processes, maternal- and neonatal outcomes, and serious adverse events that occurred during the innovation project. Chapter 4 presents a quantitative study on women’s experiences with MLC-aCTG. Chapter 5 provides a budget impact model to estimate the actual costs and reimbursement of aCTG performed in MLC and OLC from the Dutch healthcare perspective. In addition, in chapter 6, a realist review is given on how and under what circumstances continuity of care by midwives can be implemented. Finally, chapter 7 consists of the general discussion of the thesis, and chapter 8 contains the summary of the thesis in English and Dutch. 1
16 Chapter 1 REFERENCES 1. Gröne O, Garcia-Barbero M. Integrated care: a position paper of the WHO European Office for Integrated Health Care Services. International journal of integrated care 2001;1. 2. Ministerie van Volksgezondheid, Welzijn en Sport. Toegankelijkheid zorg [online]. 2023. https:// open.overheid.nl/documenten/f12a4de7-4835-4059-8630-3e6178fc5944/file (accessed 27 November, 2024). 3. Kiers B. Nederland doet mee in VBHC-kopgroep. Zorgvisie 2017;47(4):24-27. 4. De Jonge A, Downe S, Page L, et al. Value based maternal and newborn care requires alignment of adequate resources with high value activities. BMC pregnancy and childbirth 2019;19(1):16. 5. Rijksoverheid. Integraal Zorgakkoord: ‘Samen werken aan gezonde zorg’ [online]. 2022. https://www.rijksoverheid.nl/onderwerpen/kwaliteit-van-dezorg/documenten/ rapporten/2022/09/16/integraal-zorgakkoord-samen-werken-aan-gezondezorg (accessed 27 November, 2024). 6. Neppelenbroek EM, Verhoeven CJM. Handboek implementatie antenataal CTG in verloskundigenpraktijken. Amsterdam UMC, location Vrije Universiteit Amsterdam, Midwifery Science; 2022:1-102. 7. Tsiachristas A. Financial incentives to stimulate integration of care. International journal of integrated care 2016;16(4). 8. Miller HD. From volume to value: better ways to pay for health care. Health Affairs 2009;28(5):1418-28. 9. Porter ME, Teisberg EO. Redefining health care: creating value-based competition on results: Harvard business press 2006. 10. Depla A, Laureij L, Ernst-Smelt H. Working with Outcomes in Perinatal Care. Personalized Specialty Care: Value-Based Healthcare Frontrunners from the Netherlands: Springer 2021:119-25. 11. Kaplan RS, Anderson SR. Time-driven activity-based costing: a simpler and more powerful path to higher profits: Harvard business press 2007. 12. Kaplan RS, Porter ME. How to solve the cost crisis in health care. Harv Bus Rev 2011;89(9):4652. 13. Rijnders MEB (2011). Interventions in midwife led care in the Netherlands to achieve optimal birth outcomes: effects and women’s experiences. [Thesis, fully internal, Universiteit van Amsterdam]. 14. Eindrapport van de Commissie Verloskunde van het College voor zorgverzekeringen. Verloskundig Vademecum.College voor Zorgverzekeringen. Diemen; 2003. 15. Amelink-Verburg MP, Buitendijk SE. Pregnancy and labour in the Dutch maternity care system: what is normal? The role division between midwives and obstetricians. Journal of midwifery & women’s health 2010;55(3):216-25. 16. de Jonge A, Stuijt R, Eijke I, Westerman MJ. Continuity of care: what matters to women when they are referred from primary to secondary care during labour? a qualitative interview study in the Netherlands. BMC pregnancy and childbirth 2014;14:1-11. 17. Perdok H, Verhoeven CJ, Van Dillen J, et al. Continuity of care is an important and distinct aspect of childbirth experience: findings of a survey evaluating experienced continuity of care, experienced quality of care and women’s perception of labor. BMC pregnancy and childbirth 2018;18(1):1-9. 18. Rijnders M, Baston H, Schönbeck Y, et al. Perinatal factors related to negative or positive recall of birth experience in women 3 years postpartum in the Netherlands. Birth (Berkeley, Calif) 2008;35(2):107-16.
17 Introduction 19. Rayment-Jones H, Dalrymple K, Harris J, et al. Project20: Does continuity of care and communitybased antenatal care improve maternal and neonatal birth outcomes for women with social risk factors? A prospective, observational study. PloS one 2021;16(5):e0250947. 20. Homer CS, Leap N, Edwards N, Sandall J. Midwifery continuity of carer in an area of high socioeconomic disadvantage in London: a retrospective analysis of Albany Midwifery Practice outcomes using routine data (1997–2009). Midwifery 2017;48:1-10. 21. Sandall J, Turienzo CF, Devane D, et al. Midwife continuity of care models versus other models of care for childbearing women. Cochrane database of systematic reviews 2024(4). 22. Perdok H, Jans S, Verhoeven C, et al. Opinions of maternity care professionals and other stakeholders about integration of maternity care: a qualitative study in the Netherlands. BMC pregnancy and childbirth 2016;16:1-12. 23. Greenhalgh T PR WG, Westhorp G, Greenhalgh J, Manzano A, Jagosh J. What is a mechanism? What is a programme mechanism?: The RAMESES II project [online]. 2017. http://www. ramesesproject.org/media/RAMESES_II_What_is_a_mechanism.pdf (accessed 29 January, 2024). 24. Wong G WG PR, Greenhalgh T. Realist synthesis - RAMESES training materials [online]. 2013. http://www.ramesesproject.org/media/Realist_reviews_training_materials. pdf (accessed 29 January, 2024). 25. Craig P, Dieppe P, Macintyre S, et al. Developing and evaluating complex interventions: the new Medical Research Council guidance. BMJ (Clinical research ed) 2008;337. 26. Koninklijke Nederlandse Organisatie van Verloskunde (KNOV). Capaciteitsproblematiek in de verloskunde [online]. 2022. https://www.knov.nl/kennis-en-scholing/vakkennisenwetenschap/vakkennis/capaciteitsproblematiek-in-de-verloskunde (accessed 22 November, 2023). 27. Offerhaus PM, Hukkelhoven CW, de Jonge A, et al. Persisting rise in referrals during labor in primary midwife-led care in the Netherlands. Birth (Berkeley, Calif) 2013;40(3):192-201. 28. Colvin CJ, de Heer J, Winterton L, et al. A systematic review of qualitative evidence on barriers and facilitators to the implementation of task-shifting in midwifery services. Midwifery 2013;29(10):1211-21. 29. Rijksoverheid. De juiste zorg op de juiste plek [online]. 2018. https://www.rijksoverheid.nl/ documenten/rapporten/2018/04/06/rapport-de-juiste-zorg-op-de-juiste-plek (accessed 27 November, 2024). 30. van Hoof SJ, Quanjel TC, Kroese ME, et al. Substitution of outpatient hospital care with specialist care in the primary care setting: A systematic review on quality of care, health and costs. PloS one 2019;14(8):e0219957. 31. Grivell RM, Alfirevic Z, Gyte GM, Devane D. Antenatal cardiotocography for fetal assessment. Cochrane Database Syst Rev 2015(9):CD007863. 32. Excellence NIfC. Royal College of Obstetricians and Gynecologists. The use of electronic fetal heart rate monitoring. Evidence Based Clinical Guidline N. 8: London: RCOG Press, 2001. 33. Preboth M. ACOG guidelines on antepartum fetal surveillance. American family physician 2000;62(5):1184-88. 34. Spiby H. The NICE guidelines on electronic fetal monitoring. British Journal of Midwifery 2001;9(8):489-89. 35. FIGO Subcommittee on Standards on Perinatal Medicine. Guidelines for the use of fetal monitoring. Int J Gynaecol Obstet 1987;25:159-67. 36. Nijhuis JG, Essed G, van Geijn HP, Visser GHA. Foetale bewaking: Reed Business 1998. 37. Banta HD, Thacker SB. Historical controversy in health technology assessment:: The case of electronic fetal monitoring. Obstetrical & gynecological survey 2001;56(11):707-19. 38. Bernardes J, Costa-Pereira A, Ayres-de-Campos D, et al. Evaluation of interobserver agreement of cardiotocograms. International Journal of Gynecology & Obstetrics 1997;57(1):33-37. 39. Figueras F, Albela S, Bonino S, et al. Visual analysis of antepartum fetal heart rate tracings: inter-and intra-observer agreement and impact of knowledge of neonatal outcome. 2005 1
18 Chapter 1 40. Ayres-de-Campos D, Bernardes J, Costa-Pereira A, Pereira-Leite L. Inconsistencies in classification by experts of cardiotocograms and subsequent clinical decision. BJOG: An International Journal of Obstetrics & Gynaecology 1999;106(12):1307-10. 41. Di Lieto A, Giani U, Campanile M, et al. Conventional and computerized antepartum telecardiotocography. Gynecologic and obstetric investigation 2003;55(1):37-40. 42. Lotgering FK, Wallenburg HC, Schouten HJ. Interobserver and intraobserver variation in the assessment of antepartum cardiotocograms. American journal of obstetrics and gynecology 1982;144(6):701-05. 43. Verburgt T, Offerhaus P. Standpunt Uitwendige Versie. Utrecht, The Netherlands: Koninklijke Nederlandse Vereniging van Verloskundigen (KNOV), 2006. 44. Overheid. Besluit opleidingseisen en deskundigheidsgebied verloskundige [online], 2008. https://wetten.overheid.nl/BWBR0024254/2014-09-01 (accessed 27 November, 2024)
19 Introduction 1
CHAPTER 2 Inter-and intraobserver agreement of antenatal cardiotocography assessments by maternity care professionals: A prospective study Elise M. Neppelenbroek Olivier W.H. van der Heijden Henrica C.W. de Vet Amanda J.J. de Groot Darie O.A. Daemers Ank de Jonge Corine J.M. Verhoeven This chapter was published as an article in International Journal of Gynecology & Obstetrics (IJGO) 2024. Available online at https://doi.org/10.1002/ijgo.15497.
22 Chapter 2 ABSTRACT Objective In the Netherlands, antenatal cardiotocography (aCTG) to assess fetal well-being is performed in obstetrician-led care. An innovative initiative was started to evaluate whether aCTG for specific indications—reduced fetal movements, external cephalic version, or postdate pregnancy—is feasible in non-obstetrician-led care settings by independent primary care midwives. Quality assessment is essential when reorganizing and shifting tasks and responsibilities. Therefore, we aimed to assess the inter- and intraobserver agreement for aCTG assessments between and within four professional groups involved in Dutch maternity care regarding the overall classification and assessment of the various components of aCTG. Method This was a prospective study among 47 Dutch primary care midwives, hospital-based midwives, residents, and obstetricians. Ten aCTG traces were assessed twice at a 1month interval. To ensure a representative sample, we used two different sets of 10 aCTG traces each. We calculated the degree of agreement using the proportions of agreement. Results The proportions of agreement for interobserver agreement on the classification of aCTG between and within the four professional groups varied from 0.82 to 0.94. The proportions of agreement for each professional group were slightly higher for intraobserver (0.86–0.94) than for interobserver agreement. For the various aCTG components, the proportions of agreement for interobserver agreement varied from 0.64 (presence of contractions) to 0.98 (baseline heart frequency). Conclusion The proportion of agreement levels between and within the maternity care professionals in the classification of aCTG traces among healthy women were comparable. This means that these professional groups are equally well able to classify aCTGs in healthy pregnant women.
23 Observer agreement of aCTG assessments INTRODUCTION Value-based healthcare has gained considerable momentum at international and national level. It aims to organize care based on the principle of the best possible quality of care for patients, with optimal use of resources.1, 2 This also holds for maternity care. Recently, three regions in the Netherlands (Nijmegen, Zwolle, and Amsterdam) started an innovative initiative according to this principle. Healthy women whose pregnancies were monitored in midwife-led practices were offered antenatal cardiotocography (aCTG) in midwife-led care, autonomously performed and assessed by a primary care midwife, for specific indications (i.e., reduced fetal movements, external cephalic version, or postdate pregnancy [41+0 to 41+6weeks gestation]) to assess fetal well-being.3, 4 Usually, aCTGs are performed in obstetricianled care only. Within this value-based healthcare initiative, pregnant women fulfilling the above criteria were offered aCTG by their midwife either at home, in the midwifery practice, or in a community healthcare center nearby. This task shift increases value for pregnant women, as it led to a reduction of referrals and an increase in the continuity of maternity care.1, 4-6 There is growing evidence that task shifting to midwife-led care can be safe and effective.7 Unlike in Canada, New Zealand, and Scandinavian countries, the aCTG is not yet part of the diagnostic tools available to Dutch midwives. Now that access to obstetrician-led care in the Netherlands is under pressure due to capacity issues, it is important to study the quality and usability of alternative forms of care provision, such as aCTG, in midwife-led care.8 Assessment of aCTGs between groups of healthcare professionals in obstetrician-led care varies.9-14 Although the interobserver agreement in the assessment of reassuring aCTGs is fair to good, low interobserver agreement was found for non-reassuring aCTGs.11, 12 There is also variation in the assessment of the various aCTG components: baseline heart frequency, accelerations, and contractions showed good to excellent interobserver agreement in aCTG assessment while other aCTG components such as variability and the number of decelerations did not.9, 11, 14 To date, little is known about the inter- and intraobserver agreement in aCTG assessment by different groups of maternity care professionals (primary care midwives, hospital-based midwives, residents, and obstetricians). Regarding the overall classification and the various components of aCTG, the aim of this study was therefore to assess: (1) the level of interobserver agreement between the four professional groups, (2) the level of interobserver agreement within these professional groups, and (3) the level of intraobserver agreement per professional group. 2
24 Chapter 2 MATERIALS AND METHODS Study design We conducted a prospective study among four professional groups involved in Dutch maternity care. All were purposively selected from different parts of the country. The participants were provided with written information about the aim and procedure of the study and gave their written informed consent. Data about the aCTG assessments by all participants were collected between January 25, 2021 and August 29, 2021. The identity of the participants was anonymized and processed confidentially in an SPSS file. The aCTG traces used in the study were not traceable to patients. Ethical approval was requested from the Medical Ethics Committee of VU University Medical Center. They deemed the Medical Research Involving Human Subjects Act not to be applicable to our study (VUmc MEC, no. 2016.484). Setting In the Netherlands, pregnant women at low risk receive midwife-led care from primary care midwives, while women at high risk receive obstetrician-led care from obstetricians, residents, and hospital-based midwives.15 When a risk factor or a complication arises during pregnancy or childbirth, the midwife refers the woman to obstetrician-led care for consultation or transfer of care. Participants All care professionals acquired CTG assessment skills during their initial training and are legally authorized to perform CTGs. To acquire competence in performing an aCTG, the primary care midwives providing aCTGs followed a 2-day course concluded with an examination. The course consisted of the theoretical background of the CTG, the assessment of a CTG according to the International Federation of Gynecology and Obstetrics (FIGO) guidelines,16 skills needed to carry out aCTG, and training in clinical decision-making taking into account the woman’s overall well-being. To maintain competence, primary care midwives attended at least four multidisciplinary quality meetings annually with an obstetrician, organized in each region, about interpreting and evaluating aCTGs. The participating hospital-based midwives, residents, and obstetricians were already performing aCTG monitoring daily in clinical settings and were therefore, not obligated to follow a course and attend quality meetings. Measurement The participants were recruited by email. Each participant received personal login details for the Castor Electronic Data Capture system. In this secure environment,
25 Observer agreement of aCTG assessments they received an online set of 10 aCTGs with additional information about the indication for the aCTG, the woman’s pregnancy details, relevant medical history, and a scoring form to assess the aCTGs. The participants could assess the aCTGs after informed consent at a time and place convenient to them. The aCTG traces of healthy women with specific indications for aCTG (reduced fetal movements, external cephalic version, or postdate pregnancy) were obtained from the wireless portable CTG-system Sense4Baby.17 The aCTG traces were at least 30min and the paper speed was 2cm/min. We used two sets of 10 aCTG traces each to ensure a representative sample. Each set was assessed by at least five assessors per professional group. The participants were asked to assess the same 10 aCTGs twice, in a different order, at a 1-month interval (see Appendix A1 for sample size considerations). All aCTG assessments were conducted independently, that is, assessors were blinded to the results of other assessors. In the study, for the aCTG assessment, we used a classification system based on the FIGO classification (Figure 1). Although this classification is developed for intrapartum CTG, the Dutch Federation of Obstetrics and Gynecology also recommends using it for aCTG.18 The adapted classification system for various components and overall classification was provided to the assessors. Antenatal CTG classification CTG classification Baseline Heart Frequency (bpm) Accelerations and variability Decelerations Contractions Reassuring: The CTG complies with all criteria 110-150 Minimal two accelerations in a 45-minute CTG tracing Variability 5-25 bpm Absence of decelerations Maximum of two contractions per 10 minutes Absence of hypertonia Non-reassuring: The CTG deviates from one or more criteria <110 or >150 < two accelerations in a 45-minute CTG tracing Variability <5 or > 25 bpm Presence of 1 or more decelerations >two contractions per ten minutes Presence of hypertonia CTG, cardiotocography; bpm, beats per minute. Figure 1: Antenatal CTG classification system used in the study STATISTICAL ANALYSIS The analyses were performed using SPSS statistics 28.0 and Rstudio 2021.09.1. The baseline characteristics of the study population were analyzed using descriptive 2
26 Chapter 2 statistics. Frequencies and percentages are presented for categorical variables and means with standard deviations (SD) or medians with ranges for continuous variables. We expressed the inter- and intraobserver agreement among professional groups as a proportion of agreement with a 95% confidence interval (CI) because agreement is a better concept than Cohen’s kappa for answering our research questions. Cohen’s kappa is a widely-used measure of reliability, providing information on how well subjects/objects can be distinguished from each other, while agreement measures assess to which extent classifications or scores are identical.19 To calculate the degree of agreement between and within the professional groups, we used the agreement formula and calculations (R package from https://github.com/ iriseekhout/Agree), including a 95% CI. We analyzed the interobserver agreement for the aCTG classifications (reassuring, non-reassuring) and various aCTG components (baseline heart frequency, variability, presence of accelerations, decelerations, and contractions) for each possible pairing of two participants. At least five assessors in each professional group led to a minimum of 10 different pairs of assessors in each professional group, calculated by (m * (m −1)/2), where m is the number of assessors. This means the proportion of agreement for each set of 10 aCTGs was calculated on at least 100 pairwise comparisons. For the interobserver agreement between the professional groups, the classification of 10 aCTGs of each primary care midwife’s first assessment were compared with those of each hospital-based midwife, resident and obstetrician. Similarly, hospitalbased midwives were compared with residents and obstetricians, and residents with obstetricians. Two professional groups always concerned five versus five assessors, so there were 25 comparisons per aCTG and 250 pairwise comparisons per set of 10 aCTGs. The proportion of agreement of the first and second set of 10 aCTGs was statistically pooled. For the interobserver agreement within the professional groups, the proportion of agreement was calculated within five assessors. Therefore, the formula m (m − 1)/2 applies. The results were statistically pooled over the first and second set of 10 aCTGs.20 For the intraobserver agreement, the results of the first and second assessments of each individual assessor for each aCTG were compared. The results were statistically pooled over the members of each professional group.20 Whether the four professional groups differed in proportions of intra- and interobserver agreement was tested with the independent sample t-test for differences in proportions. A P-value below 0.05 was considered statistically significant. Appendix A1 justifies the statistical methods used.
27 Observer agreement of aCTG assessments RESULTS Figure 2 shows the inclusion of the participants. A total of 66 healthcare professionals were asked to participate, of whom 47 (71.2%) took part in the study. In the first round, 23 participants (at least 5 per professional group) assessed the first set of 10 aCTGs, and 24 other participants (at least 5 per professional group) assessed the second set of aCTGs. In the second round, the 47 participants were asked to assess— after a 1-month interval—the same aCTGs they assessed before, in a different order. Five participants did not complete the second round and were excluded from the intraobserver analyses. Participants invited for participation n= 66 Participants included for interobserver agreement analysis n= 47 Participants included for interobserver agreement analysis n= 5* No response n=19 Participants included for interobserver agreement analysis n= 42 *Exclusion of participants, because of incomplete surveys (primary care midwives n=2, hospitalbased midwives n=1, residents n=2) Figure 2: Flowchart of the participants 2
28 Chapter 2 Table 1 shows the baseline characteristics of the participants. The mean work experience with aCTG assessment was 7.6years (SD 6.3), varying from 3.7 (SD 1.4) (primary care midwives) to 16.7years (SD 4.0) (obstetricians). The median training in aCTG assessment yearly varied from 8.0h (primary care midwives) (range 6.0–16.0) and residents (range 1.0–30.0) to 11.5h (range 3.0–70.0) (obstetricians). In the first set of 10 aCTG traces, one out of ten aCTGs appeared to be non-reassuring according to most assessors, and in the second set, five out of 10 aCTGs appeared to be nonreassuring according to most assessors. Table 1: Baseline characteristics of the participating maternity care professionals All professionals n=47 (100%) Primary care midwives n=12 (25.5%) Hospital-based midwives n=12 (25.5%) Residents n=13 (27.7%) Obstetricians n=10 (21.3%) Age (years), mean (SD) 36.5 (9.4) 35.0 (6.7) 39.2 (13.8) 30.1 (2.6) 43.2 (6.0) Work experience in maternity care (years), mean (SD) 11.2 (8.8) 11.2 (7.3) 14.1 (12.5) 4.1 (2.2) 16.7 (4.0) Work experience in current profession (years), mean (SD) 8.4 (7.8) 11.2 (7.3) 9.9 (11.2) 3.7 (2.2) 9.2 (6.0) Work experience in CTG assessment (years), mean (SD) 7.6 (6.3) 3.7 (1.4) 8.0 (6.5) 4.0 (1.8) 16.7 (4.0) Hours of training in CTG assessment (yearly), median (range) 8.0 (0 to 70.0) 8.0 (6.0 to 16.0) 9.0 (0 to 50.0) 8.0 (1.0 to 30.0) 11.5 (3.0 to 70.0) CTG, cardiotocography; SD, standard deviation. Table 2 presents the results of the interobserver agreement on the classification of aCTG patterns (reassuring, non-reassuring) between the four professional groups (in the off-diagonal cells) and within the professional groups (in the diagonal cells). The proportions of agreement between and within the four professional groups varied from 0.82 (95% CI: 0.67–0.91) to 0.94 (95% CI: 0.87–0.98). We found no differences in proportions of agreement within the professional groups among obstetricians and
29 Observer agreement of aCTG assessments either primary care or hospital-based midwives. We did find a statistically significant difference in the proportion of agreement within the obstetricians versus residents (−0.12 [−0.03;–0.21], P-value 0.006). Table 2: Interobserver agreement in classification (reassuring and non-reassuring) of antenatal CTGs between (values off the diagonal) and within (values on the diagonal) professional groups using proportions of agreement Proportions of agreement (95% CI) Primary care midwives Hospital-based midwives Residents Obstetricians Primary care midwives 0.84 (0.72-0.91) 0.84 (0.73-0.90) 0.83 (0.73-0.90) 0.82 (0.71-0.90) Hospital-based midwives x 0.86 (0.75-0.92) 0.90 (0.81-0.95) 0.86 (0.75-0.93) Residents x x 0.94 (0.87-0.98) 0.87 (0.77-0.93) Obstetricians x x x 0.82 (0.67-0.91) CTG, cardiotocography; CI, confidence interval Table 3 describes the intraobserver agreement for the classification of aCTG patterns for the professional groups. The proportions of agreement were slightly higher for intraobserver than for interobserver agreement and varied from 0.86 (95% CI: 0.55– 0.97) to 0.94 (95% CI: 0.66–0.99) for aCTG classification for the various professional groups. We found no differences in proportions of intraobserver agreement between obstetricians and the other professional groups. Table 3 Intraobserver agreement in classification (reassuring and non-reassuring) of antenatal CTGs for professional groups in maternity care using proportions of agreement Proportions of agreement (95% CI) Primary care midwives Hospital-based midwives Residents Obstetricians 0.92 (0.62 -0.99) 0.94 (0.66 -0.99) 0.91 (0.63-0.98) 0.86 (0.55 -0.97) CTG, cardiotocography; CI, confidence interval We also investigated the inter- and intraobserver agreement on the different components (baseline heart frequency, variability, accelerations, decelerations, and contractions) of aCTG patterns between and within the four professional groups. These results are presented in Tables S1 and S2. For interobserver agreement, the proportions of agreement on the aCTG components varied from 0.64 (presence of contractions) to 0.98 (baseline heart frequency). Overall, the proportions of agreement for the various aCTG components between and within the professional 2
30 Chapter 2 groups were comparable. The proportions of agreement for each professional group were slightly higher for intraobserver than for interobserver agreement. DISCUSSION We aimed to study the inter- and intraobserver agreement between and within maternity care professionals (primary care midwives, hospital-based midwives, residents, and obstetricians) in the assessment of aCTG traces among healthy women with an indication for an aCTG (reduced fetal movements, external cephalic version, or postdate pregnancy). The proportions of agreement for interobserver agreement on the classification of aCTG between and within the four professional groups varied from 0.82 to 0.94. The proportions of agreement for each professional group were slightly higher for intraobserver (0.86–0.94) than for interobserver agreement. For the various aCTG components, the proportions of agreement for interobserver agreement varied from 0.64 (presence of contractions) to 0.98 (baseline heart frequency). To the best of our knowledge, the strength of this study is that it is the first to include both primary care midwives and obstetrician-led care professionals (hospitalbased midwives, residents, and obstetricians). For data collection, we used an efficient approach to maximize the number of aCTGs without extra work for the professionals. With at least five assessors per professional group for each set of 10 aCTGs, we guaranteed a reasonable sample of the four professional groups (n = 47). The sample size was large enough to gain sufficient power (20 aCTGs) (see Appendix A1 for sample size considerations).21, 22 However, some limitations need to be addressed. Standard criteria for agreement measures are not available. There are various suggestions in literature on how agreement levels can be labeled, although these guidelines are arbitrary.23, 24 Another limitation is that the participants in our sample, who worked in obstetricianled care, more frequently worked in the same center and region than the participating primary care midwives. The literature shows that professionals working in the same center share similar clinical cultures, which could have influenced the results (observer bias).25 We tried to minimize observer bias (1) by using multiple assessors per professional group, (2) all assessors were trained, and (3) by standardizing our procedure. Furthermore, the risk of observer bias was the same for each group of professionals; therefore, we do not expect this has impacted our results. Despite the fact that aCTGs were sent to the participants via a personal link, there is no absolute guarantee that all aCTG assessments were completed individually.
31 Observer agreement of aCTG assessments Other studies on the reliability of the overall classification of CTG patterns among healthcare professionals in obstetrician-led care showed a lower rate of observer agreement.12, 13 Ayres-de-Campos et al. found a proportion of agreement of 0.62 for normal traces, 0.42 for suspicious traces, and 0.25 for pathological traces.12 This difference in agreement levels compared to our findings may partly be related to the fact that they expressed the proportion of agreement for ante- and intrapartum CTGs together and not specifically for antepartum CTG traces as in our study. In our study, the participants assessed a sample of aCTGs selected from a population of healthy women with a specific aCTG indication, which includes a larger number of reassuring traces and thus yields a higher level of agreement.25 Previous studies showed variable results for the assessment of the various components of the aCTG: good to excellent interobserver agreement in aCTG assessment was found for baseline heart frequency, accelerations, and contractions, in contrast to other aCTG components such as the variability and decelerations.9, 11 In our study, for the various aCTG components, the proportions of agreement for interobserver agreement varied from 0.64 (presence of contractions) to 0.98 (baseline heart frequency). We suggest two main reasons for these differences. First, in our study the aCTG component deceleration was dichotomized into present or absent, instead of classifying deceleration as early, variable, or late, as defined in FIGO guideline. Second, exposure to aCTGs in clinical practice has increased in the past decade, potentially improving professionals’ assessment of aCTGs. Other studies showed that both clinical midwives and residents had better agreement than obstetricians.25, 26 We also found that the level of interobserver agreement in the classification of aCTGs within the professional group of residents was higher than within the group of obstetricians. Di Lieto et al. assessed the agreement in aCTG interpretation between experienced and inexperienced assessors. They found no differences between experienced and inexperienced professionals.14 This is in line with our results, showing comparable interobserver agreement levels between different professionals (e.g., primary care midwives and obstetricians) for the classification of aCTGs, despite differences in years of experience. In line with the literature,13 we detected a slightly higher level of intraobserver agreement than interobserver agreement for the classification of aCTGs. This observation shows consistency in the assessment of aCTGs by all maternity care professionals. It should be noted that high levels of agreement do not necessarily mean that the aCTGs have been assessed correctly. It indicates whether different professional groups provided the same assessment with a comparable level of error when classifying aCTGs. 2
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